Teacher: You are given a sentence and your task is to generate another sentence that supports the given input.
Teacher: Now, understand the problem? If you are still confused, see the following example:
In spite of this reduced heat input, the surface temperature of Venus is higher than that of the Earth.
Solution: Venus has a warmer average surface temperature than earth.
Reason: Output statement supports the input statement's claim about the temperatures of Venus being higher than the earth.

Now, solve this instance: An electromagnetic wave is a combination of an oscillating electric field and oscillating magnetic field that propagates through space, away from its source.
Student:
In an electromagnetic wave, the crests and troughs represent oscillating fields.